Multitorsion meter



Oct. 24, 1939. 1.. P. SMITH 2,176,935

MULTI'IORSION METER Filed March 4, 1957 iNVENTOR LYBRAND I? .SMIT'H ATTORNEY 5 duced by incorporating in the electrical circuit source of light there is shown a lamp 8 suitably 45 l nt exited oer. 24, 1939 2,176,935

UNITED STATES PATENT OFFICE MULTITORSION METER Lybrand P. Smith, United States Navy Application March 4, 1937, Serial No. 128,991

a claims (01. 205-25.)

(Granted under the act or Marcus, '1883, as

, amended April so, 1928; m o. G. 157) This invention relates to an apparatus for obeasy to construct and is susceptible of being ecoserving the torsion phenomena in a power shaft nomically'manufactund,

. rotating under load and more particularly to-an ,Other objects and many of the attendant adapparatus which is an improvement over that vantages of this invention will be readily appreci- 5, disclosed in U. S. Patent 2,007,220 granted to me ated as the same becomes better understood by 5 July 9 1 35 reference to the following detailed description In the aforesaid patent an apparatus was dis-' when consideredjin connection with the accomclosed wherein flashes of light definitely timed panying sheet of drawings wherein there is dewith respect to definite phases of the angular picted. one embodiment of the instant invention.

10 position of one end of a shaft whose torsion was Referring now to the drawing 1 designates the 10 to be measured were reflected from a mirror shaft whose torsion is to be measured; and the which revolved with a definite relation to the reference characters 2 and 3 denote respectively angular position o1 the other end of the shaft. the rotatable switch or contactor and rotatable As long as the shaft was free from torsional forces mirror which are driven by the shaft at spaced 1| each flash of light incident upon the rotating points through suitable driving connections idenl mirror was reflected 'at the zero mark on a suittified in general by the numerals 4 and 5. By able scale. But when the shaft twisted under reason of the employment of the aforesaid rotorsion the mirror reflected the flashes to differtatable switch or contactor 2 it is possible to utient'portions onthe scale the displacements of lize greatly simplified sets of driving connections which from the zero mark gave a measure of the each of which, for illustrative purposes, is here 20 twist in the shaft. The flashes of light were shown as a'gear 6 and a pinion 1. Some lost mocaused by a rotatable shutter interrupting a tion or slip will occur in any set of mechanical, source of constant light. Since in the construcelectrical or electro-mechanical driving connection of my apparatus itwas necessary to position tions that it is mechanically practicable to make.

the rotatable shutter and'mirror as close as pos- However, two sets of such driving connections 25 sible. to each other in' order to insure proper may be pr0vi ded that will not only have small definition of the reflected light flashes and the amountsof slip but whose slips will be so nearly production of a reasonably compact unit, it beidentical that the lost motion or slip in one set came necessary to employ a more or less comis substantially equal to that in the other. In

plicated set of mechanical, electrical or electrothe instant invention the two sets of driving con- 30 mechanical drivingconnections intermediate the .nections I and 5- are as nearly identical as it is shaft on the one hand and the shutter and mirror practicable to manufacture them in order that on the other hand for imparting motion to the I their slips or lost motionwill be substantiailyidenlatter, thus adding considerably to the cost and tical. Furthermore, the rotatable switch or concomplexity of the apparatus. tactor 2 and mirror 3 are driven at the same 35 Incarrying out my invention I have greatly speed which here by virtue of the gearing emsimplified the apparatus of the aforesaid patent ployed is some multiple of the speed of the shaft so as to make unnecessary the employment there- I. It is to be understood, however, that it is not in of the previously mentioned more. or less 'comnecessary to drive the switch and mirror at a 40 plicated driving connections. I attain this end speed in excess of that of. the shaft. .If desired, 40

. through the omission of the shutter heretofore the switch and mirror may be driven at a speed employed and by the provision of a. flashing or which is either equal to or less than the speed intermittently luminous light source. The flashof the shaft. ing-or occulting effect of 'the lightsou'rce is pro- For providing an intermittently luminous .provided for its energizationa rotatable switch connected to electrical conduits 9 and I 0 which or contactor forclosingand interrupting thecirextend to a source of electromotive force not cult at predetermined intervals, the switch or shown. The lamp 8 may be of any suitable design contactor for this purpose being driven through known to the prior art which has the property of suitable-instrumentalities by the shaft whose torgiving a flash of light when momentarily ener- 50 sion is to be measured or observed. gized. As illustrative of one such type of lamp I with the foregoing in view it is the principal may employ a stroboscopic source of light which object of my invention to provide a greatly simgives'an extremely short flash when the electriplifled apparatus for observing or measuring the cal circuit is momentarily closed. The switch or 5 torsion phenomena of a rotating shaft which is contactor 2 may be any type known to the prior art and may be designed to momentarily closethe' tainer and is interposed between the source of light 8 and the rotatable mirror 3. -'I'his screen may be either transucent with an opaque center mark or indicium. l3 or opaquewith a transparent or translucent center mark. A- telescope H or any other suitable means is disposed to receive reflected light from the mirror 3, and is provided with a scale in its field. This scale may be calibrated in any arbitrary marks, as for example, in degrees of twist or to read directly in foot-pounds of torque for the shaft. v

The operation of my apparatus may be described as follows. Let itflrstbe assumed that the shaft I is rotating without delivering power and hence is not subjected to'any torsional forces. Under these conditions every time the light 8 flashes a reflected image of the center mark or indicium l 3 will be visible at a definite position on the scale in the telescope II which: position may be taken as the zero mark." If .the shaft now delivers power with attendant torsion or twisting about its longitudinal axis the reflected image of the indicium l3 will now be seen atanother loca'-. tion on the calibrated scale within the field of the telescope M, the new location being displaced fromthe zero mark of. the scale an amount pro-* portional to the-twist or torsion in the shaft. The displacement of this image isdue to the fact that any torsion in the shaftcauses the mirror to take a different angular position over that ob-.

taining under conditions of no load. The calibrated scaleassociated with the telescope gives a direct reading of the displacement of the reflected image in terms of the torsion in the shaft.

According to the provisions of the patent statutes l have set forth the principle and. mode of operation of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that within the scope of the appended plaims the invention may be practiced otherwise than as specifically illustratedand described.

The invention herein described and claimed may be used and/or manufactured by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim:

1. An apparatus for observing the torsion phenomena of a rotating shaft, comprising in combination an electrical system including a source of light and a rotatable switch for closing the system at predetermined intervals to cause an intermittent operation of said source of light, a rotatable mirror disposed to receive light from said source, means for driving said mirror from a point on said shaft, other means for driving said switch from a point on said shaft distant from the afore-' said point, and indicating means disposed to receive light from said mirror.

2. An apparatus for. observing the torsion phenomena of a rotating shaft at a plurality of stages in a singlerotation, comprising in combination anelectrical system including "a source'of light and a rotatable switch for closing the system at predetermined intervals to cause an .in-

.termittent operation of'said source of light, a rotatable mirror disposed to receive light from said source, means for driving said switch and mirrornous upon energization thereof, means operable to cause the intermittent energization of said source, a rotatable mirror disposed to receive light from said source, means for driving said mirror from a point ori said shaft, and other means driven by. said shaft from a point thereon distant from the aforesaid point for rendering said first mentoned means operable.

4. An apparatus for observng the torsion phenomena of a rotating shaft at aplurality of stages in asingle rotation, comprising in combination a source of light which is rendered luminous upon energization thereof, ,means operable to cause the intermittent energization of said a source, a rotatable mirror disposed to receive light from said source, means for driving said mirror from a point on said shaft at a speed which is different from that of the shaft, and other means driven by said shaft froma point thereon distant from the aforesaid point for renderin said firstmentioned'means operable. I

5. An apparatus for observing the torsion phenomena of a rotating shaft, comprising in combination an electrical system including a source of light and a rotatable switch for closing the system at predetermined intervals to cause an intermittent operation of said source of light, a

rotatable mirror disposed to receive light from said source, means provided with an indicium 5 and interposed between said source of light and said mirror, means for driving said mirror from a point on said shaft, other meansfor driving said switch from a point on said shaft distant from theaforesaid point, and indicating means tatable mirror disposed to receive light from said source, means provided with an indicium and interposed between said source of light and said mirror, means for driving said switch and mirror from different points on said shaft at substantially the same speed which speed is diiferent '45 from that of said shaft, and indicating means disposed to receive a reflected image of said indicium from said mirror.

LYBRAND P. SMITH. 7o 

